| 摘要 |
PURPOSE:To obtain an extremely good pickled and finished steel surface of improved whiteness and rust resistance by immersing a hot rolled sheet in a sulfuric acid soln. then ferric sulfate-sulfuric acid soln. and adding post treatment in a nitric acid. CONSTITUTION:A hot rolled sheet is immersed in the sulfuric acid soln. under the conditions satisfying the equations I, II [(c) is wt% sulfuric acid as H2SO4, and T is liquid temp. ( deg.C)] to activate its surface, after which it is immersed in mixed soln. of ferric sulfate and sulfuric acid. In this way, the scale and the ground metal on the surface layer are dissolved away, thence the hot rolled sheet is immersed in a nitric acid soln., whereby it is finished. For example, about 5-20wt% NHO3, about 20-70 deg.C liquid temperature and about 30-120sec immersion time are adequate as these nitric acid pickling conditions. |
